ISO Great Breakfast Joint in Pasadena
I dearly love Marstons, but that place will probably be a mob scene at 9am. Green St. is a strong choice and open at 7 or 8am (maybe earlier).
I would suggest Central Park on Fair Oaks (former Soda Jerks). Attentive service, great food, pretty wide range on the menu of oatmeal, fruit + granola, waffles, eggs/bacon, etc. The other one I would suggest is Bristol Farms in South Pasadena. Their cafe (hooked on to the grocery store) is surprisingly good.
Cafe Verde, as the others have mentioned, is my first choice.
There's a nifty little down home diner way up Lake in Altadena called Fox's. Nothing fancy; just eggs, pancakes, etc.
Other places closer to central Pasadena, open early enough for you to be done before your 9:00 meeting...Dona Rosa, at the corner of Arroyo & California. Good Mexican-style breakfasts pastries. They're open at 6:00 a.m.
Another Mexican breakfast joint that is open is Tonny's, which gets mentioned often enough that if you do a search you should find a few good reviews. I like the machaca. On Lake at Orange Grove. It's open almost all the time. Literally.
Green Street Restaurant has good breakfasts; I'm not sure what time they open.
I'll second the rec for Cafe Verde, but if your meeting is at 9 a.m. then Cafe Verde won't work because it only opens at 9 a.m. Otherwise, this is a solid joint.
For something casual, might want to consider Pie N Burger, which opens by 7 a.m. on Sundays.
I also like Andy's Coffee Shop (1234 E Colorado Blvd Pasadena), which makes a really really good Machaca. Nothing fancy, just a nice little diner in the middle of Colorado Blvd.
I was in Pasadena last week-unfamiliar territory. Based on recommendations on this board I had breakfast at Cafe Verde last Sunday and it was wonderful. Small, quaint, wonderful service and menu heavy on innovative twists on classics. It's on the 900 block of Green St. There is a website and the menu is there....
We had the breakfast combo w/eggs (perfect over easy), pancakes (light and fluffy), crab cakes with eggs-Not lump crab and rather filled but tasty NTL, shrimp sandwich (on grilled sourdough with a spicy may). Fruit juices are freshly squeezed too. I saw lots of dishes being eaten by others I longed to try...it all looked so good.